Have you ever sent a document to a friend, only to find out that they didn't have the right font to view it?

A not-so-common font family on a website, might not be available to some folks. That's why it's great to use a backup font family.

<html>
 <head>
  <style>.headline {font-family: "Akzidenz-Grotesk","Helvetica", sans-serif;font-size: 1.5em;font-weight: bold;}</style>
 </head>
 <body><h1 class="headline">I shot the serif</h1></body>
</html>
]]>

That doesn't look right, does it?